CLARENCE CENTER, New York (CNN) -- The pilots of a commuter airliner that crashed late Thursday about 6 miles from a Buffalo, New York, airport discussed "significant ice buildup" on the plane's wings and windshields before the plane plunged to the ground, killing 50.

Only a few pieces of the Continental Connection Dash 8 turboprop were recognizable after the crash.

Continental Connection Flight 3407 was en route from Newark, New Jersey, to Buffalo Niagara International Airport when it went down about 10:20 p.m. ET Thursday.

Preliminary information recovered from the flight's cockpit voice and data recorders indicated that the plane underwent "severe" pitching and rolling motions after the landing gear was lowered and wing flaps were set for the approach, Steve Chealander of the National Transportation Safety Board said Friday afternoon.

"The crew discussed significant ice buildup, ice on the windshield and leading edge of the wings," Chealander said.

The plane crashed into a home in Buffalo, killing all 49 people aboard and one person on the ground. Firefighters brought under control a blaze at the crash site on Friday, blaming a natural gas leak for the fire's persistence.

Two occupants of the house survived -- a woman and her daughter -- and were released from a hospital after treatment for minor injuries, authorities said. Read about the escape

The first sign the air traffic controllers had of trouble was when Flight 3407 went off the radar.

Before that, it had been business as usual. The first officer, who was the co-pilot, had no sign of stress in her voice as she talked with air traffic control. The plane was cleared for approach.

Airline information

About a minute later, the air traffic controller said that contact with the plane had been lost and asked whether crews in other aircraft could see anything. No one responded. The controller then said there might be a plane down.

The plane was loud as it came in, as if for a takeoff rather than for a landing, said David Luce, who lives 300 feet from the crash site.

"The engines sounded like they were revving at very high speed, an unnatural sound," Luce said. "Then the engine cut out -- stopped. And within a couple of seconds, there was this tremendous explosion.

Among the dead were Beverly Eckert, widow of a September 11 attack victim, and Susan Wehle, a cantor at Temple Beth Am in Williamsville, outside Buffalo.

Also aboard was Alison Des Forges, senior Africa adviser for Human Rights Watch, a colleague confirmed. Des Forges spent four years in Rwanda documenting the 1994 genocide and had testified about the atrocity and the current situation in central Africa to Congress and the United Nations, according to the organization. Read about the victims

A representative for Colgan Air, which operated the plane for Continental, identified the crew as pilot Capt. Marvin Renslow, first officer Rebecca Shaw and flight attendants Matilda Quintero and Donna Prisco. An off-duty pilot, Capt. Joseph Zuffoletto, was also aboard.

On Friday afternoon, a minister from Renslow's church in Lutz, Florida, made a statement on the family's behalf.

"They are very proud of Marvin's accomplishments as a pilot," said Alan Burner, associate pastor at the First Baptist Church of Lutz. "They know he did everything he could to save as many lives as he could, even in the accident."

Shaw, a 25-year-old pilot from Maple Valley, Washington, had been with the airline about a year, according to her family.

In Washington, President Obama issued a statement expressing his condolences.

"Our hearts go out to the families and friends who lost loved ones," Obama said. "I want to thank the brave first responders who arrived immediately to try and save lives and who are continuing to ensure the safety of everyone in the area. We pray for all those who have been touched by this terrible tragedy to find peace and comfort in the hard days ahead."

The Erie County Medical Examiner's Office established a command post at the scene and had investigators there, a statement from the office said. Officials said relatives of passengers aboard the flight should call 800-621-3263 for information. Watch what iReporter captured on film

Thursday's incident is the first fatal crash of a commercial airliner in the United States since August 2006, when Comair Flight 5191 crashed while attempting to take off from the wrong runway near Lexington, Kentucky.